EP 1 159 218 B1 discloses an electronic safety system for an elevator in which safety shut-off is performed when an unsafe state is determined. The electronic safety system comprises a safety control device and a communication bus which allows control and data signals to be interchanged between a control device based on a microprocessor and various components which comprise bus nodes. The bus nodes are in a form such that they form an interface for sensors, contacts and switches. A safety control device processes the data received from the bus nodes and determines whether there is an unsafe state. In the event of an unsafe state, the safety control device sends a stop signal to the drive and brake unit of the elevator, with a status signal which indicates the unsafe state also being sent to the control device.
In the case of the safety control device which is known from EP 1 159 218 B1, the control device of the elevator is not intended to process any information from the bus nodes, but rather the control device actually obtains the processed information from the bus nodes from the safety control device in order to allow a faster reaction by the control device of the elevator. The safety control device undertakes the safety tasks on its own and is assigned an elementary role.